The present invention relates generally to actuator control in an automatic performance of a musical instrument. More particularly, the present invention relates to a keyboard musical instrument which includes actuators for operating performance operators and executes an automatic performance by controlling the actuators in accordance with performance instructions, as well as an automatic performance programs.
There have heretofore been known auto player pianos (auto playing pianos or automatic performance pianos) provided with solenoids that are actuators (drive device) for driving keys that are performance operators. The auto player pianos are constructed to execute an automatic performance by driving the solenoids on the basis of performance information to thereby move or operate the keys with plungers (movable members) of the solenoids, as disclosed for example in Japanese Patent No. 4222210 (hereinafter referred to as “Patent Literature 1”).
The auto player piano disclosed in Patent Literature 1 includes key sensors each for detecting a stroke position or velocity of a corresponding one of the keys, and plunger sensors each for detecting a plunger position or plunger velocity of a corresponding one of the solenoids. The auto player piano feeds, back to servo control performed on the basis of the performance information, a signal based on a stroke position or velocity of a key detected by each of the key sensors and a plunger position or plunger velocity detected by each of the plunger sensors. In this way, the auto player piano can enhance an accuracy of driving, by each of the solenoids, of the corresponding key. However, the technique disclosed in Patent Literature 1 does not take into consideration accurate correlative relationship between action of the key and action of the solenoid. Thus, in a quick performance style where the key cannot appropriately follow motion of the solenoid (e.g., in a performance style where one key is hit successively at quick speed), the action of the key and the action of the solenoid cannot be appropriately harmonized with each other, which would cause unwanted operational disharmony or discrepancy between the action of the key and the action of the solenoid. Thus, the key and the plunger (movable member) of the solenoid may sometimes anomalistically move out of contact with, i.e. separate or move away from, each other and hit each other to generate driving noise (sound). In addition, the motion of the keys would become unstable so that an accurate automatic performance sometimes cannot be executed.